The Knights SR-15 is listed by name and cannot be made CA-Legal. If it's on the list there's no way to legally own it in CA, unless you owned it before the ban and registered it with the state.

You will need to find a lower receiver or rifle that is not on either the A list or the B list from that flowchart. These are called Off-List Lowers, abbreviated OLL.

Once you do that, if you want a fully-functional rifle (ability to use your 30-round mags and detach them with a finger press) you have to remove all the "evil" features (including pistol grip). Four ways to replace the pistol grip (in alphabetical order): 1) California Rifles U-15 Stock, 2) Exile Machine Hammerhead Grip/Adapter, 3) Monsterman Grip, 4) Solar Tactical Kydex Grip Wrap. But unfortunately no product can make a listed receiver legal.